JPH0549603B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention removes catalytic impurities from cyclic dichlorophosphazene trimers to produce highly purified trimers that do not polymerize at or below 300°C in the absence of added catalyst. Concerning what to do. The present invention provides a standardized starting material that, when polymerized at a predetermined temperature in the presence of a predetermined amount of a selected catalyst, produces a consistently reproducible polymerized product. provide.
In other words, the present invention makes it possible to control the molecular weight (dilute solution viscosity) of the polymer. The products of the process of the invention are sometimes referred to herein as non-self-polymerizing trimers.

Dichlorophosphazene trimers are commonly purified by separating the cyclic trimer from the linear oligomer. However, this "purified" trimer contains traces of catalytic impurities, sometimes referred to as protic impurities (ie, materials that can act as proton donors). These catalytic or protic impurities include
Examples include hydrolyzed cyclic and linear trimers, including water, methanol, ethanol, isopropanol, alkylamines and other basic materials, hydrochloric acid, and phosphoramidates. The phrase "trace" refers to parts per million (hereinafter
(PPM), for example, 10 to 1000 PPM.

These trace amounts of catalytic impurities have a catalytic effect during the polymerization. Since the amounts of these vary in each batch of trimer, the products of the polymerization operation are usually not reproducible.

Some of the catalytic impurities are easily removed. For example, water is easily removed by drying. Other catalytic impurities, such as hydrolyzed trimer, are very difficult to remove under normal conditions.

Since it is desirable to remove catalytic impurities,
And because of the difficulties involved, it is difficult to remove all such impurities, i.e., non-self-polymerizing cyclic trimers, even at temperatures as high as 300°C in the absence of an added catalyst. Work has been carried out towards purification to the extent of producing cyclic trimers that do not polymerize.

Non-self-polymerizing trimers are described in Colclough and Gee, Journal of Polymer Science, Part C, No.
16, pp. 3639-3642 (1968). Colclough et al. subjected this to a series of operations including recrystallization, refluxing at 130 °C over BaO in a dry nitrogen atmosphere, passing the trimer vapor over phosphorus pentoxide at 130 °C, followed by repeated sublimation. Therefore, it is being manufactured. This is a very complex multi-step procedure.

Non-self-polymerizing trimers may also be made by the method described in Fieldhouse et al., US Pat. No. 4,327,063. In the method of this patent, traces of protic impurities are removed by treating a cyclic dichlorophosphazene trimer with boron trihalide under specific temperature and pressure conditions.

The invention filed herein is disclosed in U.S. Pat. No. 4,327,063.
This method provides an alternative to the method in issue.
Although, like Colclough et al., it relies on phosphorus pentoxide (P ₂ O ₅ ), the present invention is directed to a method that is much less complex and requires less equipment and time than Colclough et al.'s method.

The present invention relates to a method for purifying a cyclic dichlorophosphazene trimer (hereinafter "the trimer") that is substantially pure except for catalytic impurities.

The method of the present invention comprises the following steps: (a) converting the trimer in the liquid phase into solid P ₂ O ₅ ;
(b) further subjecting the product resulting from step (a) to a single purification step by sublimation, melt filtration or distillation; and recovering a trimer that is substantially free of catalytic impurities and that does not polymerize at or below 300° C. in the absence of added catalyst.

The cyclic dichlorophosphazene trimer treated in the present invention, that is, the cyclic dichlorophosphazene trimer that is substantially pure except for catalytic impurities, is readily available commercially. This usually contains traces of catalytic impurities, as described above.

Contacting the liquid phase trimer with P ₂ O ₅ comprises:
This is easily accomplished by melting the trimer (mp about 115° C.), adding the P ₂ O ₅ as a powder, and forming a mixture of the two. At this stage, the amount of trimer (including catalytic impurities) preferably ranges from about 2% to about 10% by weight.
P ₂ O ₅ can be used to increase the efficiency of contact between P ₂ O ₅ and catalytic impurities, for example by stirring with a magnetic stirrer or other stirrer, or by stirring for a mixture. It shall include stirring operations by vibrating the mixture by moving the container.

This step causes the reduction of catalytic impurities to phosphates. In the case of hydrolyzed trimer impurities, hydrolyzed trimer reaction products of reduced volatility and substantially increased clay are thereby produced, and such reaction products and other reactions This makes it possible to separate the catalytic impurities from the cyclic trimer in a further separation step.

Preferably, the step comprising contacting _{with P2O5} is about
At a temperature ranging from 155°C to about 165°C, for about 15 minutes to about
It shall take place over a period of 25 minutes.

The step involving contact with P ₂ O ₅ shall preferably be carried out under a dry inert gas atmosphere, such as argon or nitrogen, to prevent further catalytic impurities from entering from the environment.
This allows this step to be carried out into the glove box, i.e. with an inert gas atmosphere, an aerodynamic system that allows the object to enter the box without disturbing the protective atmosphere.
This is easily accomplished by carrying out the task in a box equipped with gloves attached to the walls of the box and used to move objects inside the box. Contacting (reaction) is conveniently carried out in a container equipped with heating means, for example a heating mantle, inside a glove box.

Turning now to a single purification step performed on the product produced from the P ₂ O ₅ contacting step:
Such purification relies on the volatility or viscosity differences mentioned above.

Turning first to the final purification step, when purification is carried out by sublimation, this consists of heating the product in vacuo on the cooled product and
This is easily done by recovering the substantially pure cyclic trimer by condensing it onto a cold finger.

Sublimation converts the cooled product of _{the P2O5} contact step into
to a temperature in the range of about 50°C to about 90°C, most preferably about 65°C to about 75°C, for a period of time in the range of about 10 hours to about 25 hours, as normally obtained using a conventional vacuum pump. high vacuum, e.g. 0.06mmHg to
This is preferably carried out by heating under 0.10 mm Hg and using city water, for example at a temperature in the range of 10-20° C., to cool the cold finger. The product of the P ₂ O ₅ contacting step is easily cooled to room temperature prior to the sublimation step by allowing it to cool at ambient conditions, for example over a period of 20 to 40 minutes.

When the final purification step is carried out by sublimation,
The P ₂ O ₅ contacting step is carried out in a globe box at the bottom of the sublimer surrounded by a heating mantle, and after the P ₂ O ₅ contacting step the mantle activity is stopped and the product is allowed to cool. In addition, the top of the sublimator with a cold finger can be connected in the glove box, and the sublimator can be evacuated and removed from the glove box without ingress of catalytic impurities. It is easily accomplished. Once the sublimator is out of the glove box, connect the water cooling line to the cold finger, heat the bottom of the sublimator, for example in an oil bath, and pump down to the operating vacuum using a vacuum pump. The purified trimer condenses on the cold finger, which discontinues the water flow, transfers the back of the sublimator into the glove box, and transfers the purified trimer from the cold finger to the glove box. It is easily recovered by scraping it out under an inert protective atmosphere.

Turning now to the final purification step, where the final purification is carried out by melt filtration, this step is usually carried out on the melt product of the P ₂ O ₅ treatment step. This allows the product of the P ₂ O ₅ treatment step to be passed through a glass fiber filter, such as Whatman ( This is easily accomplished by pouring directly into the polymerization tube through GF/A glass fiber paper, thereby collecting the purified trimer into the polymerization tube, thus allowing the predetermined It is then ready for polymerization therein by contact with an added amount of polymerization catalyst to obtain a predetermined polymerization result. If the product of the P ₂ O ₅ contacting step has solidified, it is allowed to melt without interruption for filtration. If the final purification is to be carried out by melt filtration, the P ₂ O ₅ contacting step is easily carried out in a boiling flask in a glove box under an inert atmosphere.

Turning now to the final purification step, where the final purification is carried out by distillation, this step consists of P ₂ O ₅
This is easily accomplished by subjecting the product of the contacting step to distillation at, for example, about 100° C. to 120° C. under high vacuum, e.g. 0.05 to 0.10 mm Hg. In this case, the P ₂ O ₅ contacting step is conveniently carried out in a distillation apparatus under a protective atmosphere in a glovebox to minimize handling requirements.

The present invention uses only one purification step after P ₂ O ₅ contact and uses commercially available starting materials.
By utilizing the starting material without having to subject it to purification treatment prior to the P ₂ O ₅ contacting step, it is now possible to recover trimer substantially free of catalytic impurities. This product is
When polymerized under predetermined catalyst temperature and time conditions, it provides a predetermined polymer, ie, a predetermined molecular weight/dilute solution viscosity.

The invention is illustrated in the following working examples.

In this example, the equipment used includes a glove box with an aerodynamic device, which is available from Vacuum Atmospheres, Inc. Other equipment used to carry out the operation of this example includes a 3 1/2 inch diameter bottom surrounded by a heating mantle through which city water is moved for cooling. removable, equipped with a 1 inch diameter cold finger, having water inlets and outlets, and also means for connection with a vacuum pump to provide a vacuum within the sublimator. A sublimator having a top portion is included.

EXAMPLE A container of commercially available cyclic dichlorophosphazene trimer, P ₂ O ₅ powder, pure except for catalytic impurities, and a sublimator free of catalytic impurities are introduced into a glove box and passed through its aerodynamics into a glove box. Once introduced into the box space, they are protected from contamination by the protective argon atmosphere in the glove box.

Using the glove in the glove box,
100 g of commercially available trimer in powder form is added into the bottom of the sublimator and the heating mantle is energized to provide a temperature of 160° C. which melts the trimer. Add 5 g of P ₂ O ₅ powder (5% by weight based on the weight of the crude trimmer) into the molten trimmer at the bottom of the sublimer and bring the bottom of the sublimer to a temperature of about 160 °C.
Hold for 20 minutes while stirring to stir the mixture. The mantle is then turned off and the mixture is allowed to cool to room temperature over a period of 20-30 minutes. The top of the sublimator is then connected, a vacuum is applied internally to protect the contents therein from contamination, and the sublimator is removed from the glove box. Next, connect the water line to the cold finger at the top of the sublimator, immerse the bottom of the sublimator in an oil bath at 70 °C, and use a vacuum pump to provide a vacuum of 0.05 mmHg. Hold these conditions overnight. Substantially pure trimer sublimates and condenses on the cold finger. At this point, the sublimator is disconnected from the water cooling line and returned to the protective atmosphere of the glove box, where it is dismantled and the purified trimmer is scraped from the cold finger into a pan. Still in the glove box, the purified trimer is introduced from the dish into the dried polymerization tube and the tube is sealed. Place the sealed tube in a circulating air oven at 270°C for one week. No polymerization occurs.

Alternatively, the starting material, instead of being purified, is introduced directly into the polymerization tube and the polymerization tube is placed in a circulating air oven at 250° C. for 31 hours. Thus, 21% conversion of the cyclic trimer to polymer occurs (dilute solution viscosity in toluene of 2.40 and 0% gel).

Alternatively, the P ₂ O ₅ treatment can be carried out in a trimmer for purification under the protective atmosphere of a glove box.
This is done by introducing 100 g into a 250 ml boiling flask and melting therein. _{P2O5 powder}
2.5g was introduced into it, the temperature was raised to 170℃,
Keep the mixture at 170 °C for 20 minutes while stirring. At the end of a period of 20 minutes, the mixture is purified by melt filtration under a protective atmosphere in a glove box. This is done by pouring the mixture onto Whattman GF/A glass fiber paper and collecting the filtrate in a sealed polymerization tube. No polymerization occurs when the polymerization tube is held at 270°C in a circulating air oven for one week. Trimer starting materials not treated by the method of the invention polymerize significantly under these polymerization conditions.

0.05mm of the mixture obtained from _the above _P2O5 treatment
A non-self-polymerizable trimer is also obtained by subjecting it to distillation of Hg under vacuum at 110°C.

Two batches of purified trimer were prepared from the above example.
Produced by P ₂ O ₅ contact and sublimation steps.
30 g of each batch is mixed with triphenyl phosphate-boron trichloride catalyst (0.05 g) in a polymerization tube and the polymerization mixture is kept at 220 DEG C. in a circulating air oven for 16 hours. In each case there is a conversion of about 40%,
The polymer product has an intrinsic viscosity of about 0.9.

Other variations will be obvious to those skilled in the art. It is therefore considered that the scope of the invention is defined by the claims that follow.

Claims (1)

[Claims] 1. A method for purifying a cyclic dichlorophosphazene trimer that is substantially pure except for catalytic impurities, the method comprising: (a) converting the trimer in a liquid phase to P; ₂ O ₅ and about 120℃
(b) subjecting the product resulting from step (a) to a single purification by sublimation, melt filtration or distillation; and recovering trimer which is substantially free of catalytic impurities and which does not polymerize at or below 300° C. in the absence of added catalyst. 2. The method of claim 1, wherein 2 P ₂ O ₅ is used in an amount ranging from about 2% to about 10% by weight of the trimer (including catalytic impurities). 3. The method of claim 2, wherein step (a) is carried out using agitation. 4. The method of claim 3, wherein step (b) is carried out by sublimation. 5. The method of claim 4, wherein step (a) is carried out at a temperature in the range of about 155°C to about 165°C. 6. The method of claim 5, wherein step (a) is carried out for a period of time ranging from about 15 minutes to about 25 minutes. 7. Sublimation is carried out by heating the mixture under vacuum to a temperature in the range of about 65°C to about 75°C and condensing the product onto a cold finger cooled with city water. , the method according to claim 4.